MPX is really a interesting thing for me, and actually I'm trying to build MPX on my ubuntu. However, I can't find a lot of information of installation MPX. According to the instruction of installation MPX on your MPX website, the way you recommanded to install MPX is to upgrade my xserver. I followed each step on "http://wiki.x.org/wiki/ModularDevelopersGuide". While I was doing the command, "PATH=/tmp/modular/bin:$PATH ./util/modular/build.sh /tmp/modular", I got an error and then build.sh stoped. The error message was "Checking for GL... configure: error: Package requirements (glproto >= 1.4.9 gl>= 7.1.0) were not met: No package 'gl' found"I'm sure that I've installed package x11proto-gl-dev as glproto's package. However, I can't gl package. I don't know which package I need to install. Sorry for bothering you. I think this is a stupid question because nobody discuss this issue on the Internet so that is not a problem for them. Hopefully you can help me please. Here is my email address: shhuango@hotmail.com.Thanks for reading this.